An image processing method (300) and an image processing apparatus (1200) are provided. The image processing method measures a myocardial performance index (MPI), the image processing method including: obtaining a region of interest (ROI) for measuring the MPI, based on signal levels of an input signal and an output signal of a heart spectrum image (310); obtaining a plurality of marker areas, within the obtained ROI, wherein at least one marker for measuring the MPI is located in each of the plurality of marker areas, based on at least one from among a feature value of the input signal and a feature value of the output signal (320); and obtaining the at least one marker for each of the plurality of marker areas (330).